This relates generally to imaging devices, and more particularly, to imaging devices having selective image signal readout and processing capabilities.
Image sensors are commonly used in electronic devices such as cellular telephones, cameras, and computers to capture images. In a typical arrangement, an electronic device is provided with an array of image pixels arranged in pixel rows and pixel columns. The image pixels contain a photodiode for generating charge in response to image light. Circuitry is commonly coupled to each pixel column for reading out image signals from the image pixels.
In certain applications, it may be desirable to read out and/or process image signals from only some of the image pixels in an image pixel array (i.e., image signals from some of the image pixels in the pixel array are “skipped”) in order to reduce power consumption of the imaging system. In conventional imaging systems, the ratio of image pixels from which image signals are read out and processed to image pixels that are “skipped” is constant across the entire image pixel array (i.e., image signals from only one out of every two image pixels in the array is read out and processed, image signals form only one out of every ten image pixels is read out and processed, or image signals form only one out of every fifteen image pixels in the array is read out and processed, etc.).
In applications such as wide-angle image capture with a digital camera “surround-view” image capture in automotive applications, however, image data may be more abundant in some parts of an image, while other parts of the image include less image data. In these applications, it may be desirable to use a different skipping ratio for pixels that generate image data in parts of the image that include more abundant data, while using a different skipping ratio for pixels that generate image data in parts of the image that include less abundant image data. Because conventional image sensors only use one skipping ratio for the entire image frame, however, the number of image pixels from which image signals are read out and processed will remain high in portions of the image with abundant image data in order to increase the resolution of the portions of the image with less abundant image data. This, however, increases power consumption of the imaging system. Alternatively, the number of image pixels from which image signals are read out and processed will be reduced in order to decrease the overall power consumption of the imaging system. This, however, decreases the resolution of portions of the image with less abundant image data.
It would therefore be desirable to be able to provide imaging systems with improved pixel readout capabilities.